The Value of Evidence in Decision-Making

The Value of Evidence thesis (VE) tells us to gather evidence before deciding in any decision problem, if the evidence is free. This appar- ently plausible principle faces two problems. First, it fails on evidence externalism or nonclassical decision theories. Second, it’s not general enough: it tells us to prefer gaining free evidence to gaining no evi- dence, but it doesn’t tell us to prefer gaining more informative evidence to gaining less informative evidence when both are free. This paper defends an alternative value-of-evidence principle that solves the above two problems. We call it ‘the Comparative Value of Evidence for the Resolute (CVER).’ CVER not only generalizes VE to the comparative case but is also compatible with evidence externalism and nonclassical decision theories. Our argument, if successful, broadens the scope of the value-of-evidence principle and shows that it’s more robust than previously imagined.